Explain the physical and chemical agents in control of micro-organism.
Answers
Microorganisms are controlled by means of physical agents and chemical agents. Physical
agents include such methods of control as high or low temperature, desiccation, osmotic
pressure, radiation, and filtration. Control by chemical agents refers to the use of disinfectants,
antiseptics, antibiotics, and chemotherapeutic antimicrobial chemicals.
Basic terms used in discussing the control of microorganisms include:
1. Sterilization
Sterilization is the process of destroying all living organisms and viruses. A sterile object is one
free of all life forms, including bacterial endospores, as well as viruses.
2. Disinfection
Disinfection is the elimination of microorganisms from inanimate objects or surfaces.
3. Decontamination
Decontamination is the treatment of an object or inanimate surface to make it safe to handle.\
3. Disinfectant
A disinfectant is an agents used to disinfect inanimate objects but generally to toxic to use on
human tissues.
4. Antiseptic
An antiseptic is an agent that kills or inhibits growth of microbes but is safe to use on human
tissue.
6. Sanitizer
A sanitizer is an agent that reduces, but may not eliminate, microbial numbers to a safe level.
7. Cidal
An agent that is cidal in action will kill microorganisms and viruses.
8. Static
An agent that is static in action will inhibit the growth of microorganisms.
Keep in mind that when evaluating or choosing a method of controlling microorganisms, you
must consider the following factors which may influence antimicrobial activity:
1. the concentration and kind of a chemical agent used;
2. the intensity and nature of a physical agent used;
3. the length of exposure to the agent;
4. the temperature at which the agent is used;
5. the number of microorganisms present;
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6. the organism itself; and
7. the nature of the material bearing the microorganism.